Diagnosing mental health problems using Artificial Intelligence / Machine Learning techniques
There's a strong sentiment towards the idea that medical diagnosis is largely Abductive Reasoning. See this presentation for additional details.  One approach to automated abductive reasoning is parsimonious covering theory.

If you want a relatively in-depth look at all of this, check out the book Abductive Inference Models for Diagnostic Problem-Solving . 

Expert systems have also been shown to work very well for medical diagnosis. As far back as the 1970's, systems like MYCIN could beat human experts in terms of diagnosis and treatment plans. 

From what I can tell, there doesn't seem to be any reason in principle to think that AI/ML can't be used across the board for medical diagnosis, mental health or otherwise.